1. Field of the Invention
The present invention relates to a projector and, more specifically, to a projector having a lens cap.
2. Description of the Background Art
A projector is one of devices for displaying images on a screen. As shown in FIG. 9, such a projector 101 has a lens 102 for projecting an image mounted thereon. On lens 102, a focus ring 103 for focusing is mounted. When projector 101 is not in use, a prescribed lens cap is put on focus ring 103, so as to protect lens 102.
An example of such a lens cap for protecting lens 102 will be described with reference to the lens cap disclosed in Japanese Patent Laying-Open No. 04-094271. Referring to FIG. 10, a lens cap 104 includes a front portion 104a covering lens 102, and a cylindrical side portion 104b formed along the outer circumference of front portion 104a. On side portion 104b, a lock 104c for retaining a string is formed.
Projector 101 has such an arrangement that a string 106 connected to projector 101 is passed through lock 104c, so that lens cap 104 will not be lost.
The conventional projector, however, has the following problem. Referring to FIG. 10, lock 104c of lens cap 104 protrudes outward from side portion 104b. 
Projector 101 sometimes has such a structure that the lens is not protruded from front panel 101a, in view of lens protection and better design, as shown in FIG. 11.
In such a projector 101, a space between focus ring 103 and front panel 101a is relatively narrow, and therefore, when lens cap 104 is put on focus ring 103, lock 104c may interfere with front panel 101a. 
In some cases, the position (along the circumferential direction) for attaching lens cap 104 is limited in order to avoid such interference.